This diagram explains the balance and hierarchy of the composition. On the back, the Yellow and blue areas show us the visual balance between them. Even though the yellow area has the Author illustration and the text "Brilliant and disturbing" the blue area equalizes the visual weight with the black stripe. On the front, the purple areas show the safe areas around the central artwork.
The orange lines explains the intended direction that the eye will follow. Through visual conductors, the design will invite to go from the front to the back of the book.